Search Publications
Discovery of an optical and X-ray synchrotron jet in NGC 7385
Birkinshaw, M.; Worrall, D. M.; Rawes, J.
We report the discovery of optical and X-ray synchrotron emission from the brighter radio jet in galaxy NGC 7385 using data from HST and Chandra. The jet has a projected length of 5 kpc and a similar morphology to other known optical jets in low-power radio galaxies. We also report a strong jet-cloud interaction which appears to be deflecting the …
The infrared and molecular environment surrounding the Wolf-Rayet star WR 130
Noriega-Crespo, A.; Cichowolski, S.; Pineault, S. +3 more
We present a study of the molecular CO gas and mid/far-infrared radiation arising from the environment surrounding the Wolf-Rayet (WR) star 130. We use the multiwavelength data to analyse the properties of the dense gas and dust, and its possible spatial correlation with that of young stellar objects (YSOs). We use 12CO J=1-0 data from …
Discovery of blue companions to two southern Cepheids: WW Car and FN Vel
Kovtyukh, V.; Szabados, L.; Chekhonadskikh, F. +2 more
A large number of high-dispersion spectra of classical Cepheids were obtained in the region of the Ca II H+K spectral lines. The analysis of these spectra allowed us to detect the presence of a strong Balmer line, Hɛ, for several Cepheids, interpreted as the signature of a blue companion: the presence of a sufficiently bright blue companion to the…
Broad-band X-ray spectra of anomalous X-ray pulsars and soft γ-ray repeaters: pulsars in a weak-accretion regime?
Zezas, A.; Trümper, J. E.; Kylafis, N. D.
We present the results from the analysis of the broad-band X-ray spectra of five anomalous X-ray pulsars (AXPs) and soft γ-ray repeaters (SGRs). We fit their Suzaku and INTEGRAL spectra with models appropriate for the X-ray emission from the accretion flow on to a pulsar. We find that their X-ray spectra can be well described with this model. In p…
Oxygen emission in remnants of thermonuclear supernovae as a probe for their progenitor system
Kaastra, J. S.; Kosenko, D.; Blinnikov, S. I. +3 more
Recent progress in numerical simulations of thermonuclear supernova explosions brings up a unique opportunity in studying the progenitors of Type Ia supernovae. Coupling state-of-the-art explosion models with detailed hydrodynamical simulations of the supernova remnant evolution and the most up-to-date atomic data for X-ray emission calculations m…
Is HE 0436-4717 Anemic? A deep look at a bare Seyfert 1 galaxy
Gallo, L. C.; Vasudevan, R.; Bonson, K.
A multi-epoch, multi-instrument analysis of the Seyfert 1 galaxy HE 0436-4717 is conducted using optical to X-ray data from XMM-Newton and Swift (including the Burst Alert Telescope). Fitting of the UV-to-X-ray spectral energy distribution shows little evidence of extinction and the X-ray spectral analysis does not confirm previous reports of deep…
Kathryn's Wheel: a spectacular galaxy collision discovered in the Galactic neighbourhood
Parker, Quentin A.; Stupar, Milorad; Frew, David J. +4 more
We report the discovery of the closest collisional ring galaxy to the Milky Way. Such rare systems occur due to `bulls-eye' encounters between two reasonably matched galaxies. The recessional velocity of about 840 km s-1 is low enough that it was detected in the Anglo-Australian Observatory/UK Schmidt Telescope Survey for Galactic H α e…
A weak lensing comparability study of galaxy mergers that host AGNs.
Courbin, F.; Harvey, D.
We compared the total mass density profiles of three different types of galaxies using weak gravitational lensing: (i) 29 galaxies that host quasars at bar{z}∼ 0.32 that are in a post-starburst quasar (PSQ) phase with high star formation indicating recent merger activity, (ii) 22 large elliptical galaxies from the Sloan Lens ACS Survey (SLACS) sam…
MLS110213:022733+130617: a new eclipsing polar above the period gap
Costa, J. E. R.; Oliveira, A. S.; Rodrigues, C. V. +4 more
This study confirms MLS110213:022733+130617 as a new eclipsing polar. We performed optical spectroscopic, polarimetric and photometric follow-up of this variable source identified by the Catalina Real Time Transient Survey. Using the mid-eclipse times, we estimated an orbital period of 3.787 h, which is above the orbital period gap of the cataclys…
Exploring the active galactic nuclei population with extreme X-ray-to-optical flux ratios (fx/fo > 50)
Ballo, L.; Carrera, F. J.; Watson, M. G. +8 more
The cosmic history of the growth of supermassive black holes in galactic centres parallels that of star formation in the Universe. However, an important fraction of this growth occurs inconspicuously in obscured objects, where ultraviolet/optical/near-infrared emission is heavily obscured by dust. Since the X-ray flux is less attenuated, a high X-…